This invention relates to a method of and apparatus for measuring the magnetic properties of electrical steels.
Hitherto, a test known as the Epstein Square Test has been extensively used to measure and verify the magnetic properties of electrical steels. This test is carried out off-line and requires relatively narrow strips to be cut from a sheet or strip of electrical steel to be tested. It is, consequently, time consuming to perform and wasteful in terms of the steel to be tested. Also, the test is not a true indication of power loss along the complete length of the strip or sheet from which the narrow sample strip was cut.
On line systems more known in which a sheet or strip of grain oriented electrical steel is passed over or between flux inducing coils of a magnetizing system, the resulting induced magnetic flux in the strip or sheet being measured by one or more search coils positioned above and below the strip or sheet. The presence of the search coils precludes ready access to the strip or sheet under test and the close proximity of the search coil to the steel sheet or strip inhibits visual inspection of the strip or sheet surface during testing.